For example, as one of methods for manufacturing silicon single crystal, there is widely known the Czochralski method for melting a silicon polycrystalline raw material in a crucible, bringing seed crystal into contact with a melt surface, and pulling the seed crystal, thereby growing the single crystal.
In manufacture of the single crystal based on the Czochralski method, it is known that a metallic impurity of a quartz crucible that accommodates raw material polycrystalline serving as a melt and this melt affects defect density of single crystal to be manufactured. For example, in Patent Literature 1, a synthetic quartz crucible having small impurity content (Al, Fe, Ni, Cr, or the like) in a synthetic layer is used, and manufacturing single crystal with micro defects corresponding to 3/cm2 or less.